OpenAI Chat Completion

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://api.openai.com/schemas/openai/chat-completion.json",
  "title": "OpenAI Chat Completion",
  "description": "Represents a chat completion response generated by the model, containing one or more message choices with associated metadata and token usage.",
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "description": "A unique identifier for the chat completion"
    },
    "object": {
      "type": "string",
      "const": "chat.completion",
      "description": "The object type, always chat.completion"
    },
    "created": {
      "type": "integer",
      "description": "Unix timestamp of when the completion was created"
    },
    "model": {
      "type": "string",
      "description": "The model used for the chat completion"
    },
    "choices": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "index": {
            "type": "integer",
            "description": "The index of the choice in the list"
          },
          "message": {
            "$ref": "#/$defs/ChatMessage"
          },
          "finish_reason": {
            "type": "string",
            "enum": ["stop", "length", "tool_calls", "content_filter"],
            "description": "The reason the model stopped generating tokens"
          }
        }
      },
      "description": "A list of chat completion choices"
    },
    "usage": {
      "$ref": "#/$defs/Usage"
    },
    "system_fingerprint": {
      "type": "string",
      "description": "Fingerprint representing the backend configuration"
    }
  },
  "required": ["id", "object", "created", "model", "choices"],
  "$defs": {
    "ChatMessage": {
      "type": "object",
      "properties": {
        "role": {
          "type": "string",
          "enum": ["system", "user", "assistant", "tool"],
          "description": "The role of the message author"
        },
        "content": {
          "description": "The contents of the message",
          "oneOf": [
            { "type": "string" },
            { "type": "null" }
          ]
        },
        "tool_calls": {
          "type": "array",
          "items": {
            "$ref": "#/$defs/ToolCall"
          },
          "description": "Tool calls generated by the model"
        },
        "refusal": {
          "type": ["string", "null"],
          "description": "The refusal message if the model refused to respond"
        }
      },
      "required": ["role"]
    },
    "ToolCall": {
      "type": "object",
      "properties": {
        "id": {
          "type": "string",
          "description": "The ID of the tool call"
        },
        "type": {
          "type": "string",
          "const": "function"
        },
        "function": {
          "type": "object",
          "properties": {
            "name": {
              "type": "string",
              "description": "The name of the function to call"
            },
            "arguments": {
              "type": "string",
              "description": "The arguments as a JSON string"
            }
          },
          "required": ["name", "arguments"]
        }
      },
      "required": ["id", "type", "function"]
    },
    "Usage": {
      "type": "object",
      "properties": {
        "prompt_tokens": {
          "type": "integer",
          "description": "Number of tokens in the prompt"
        },
        "completion_tokens": {
          "type": "integer",
          "description": "Number of tokens in the generated completion"
        },
        "total_tokens": {
          "type": "integer",
          "description": "Total number of tokens used"
        }
      },
      "required": ["prompt_tokens", "completion_tokens", "total_tokens"]
    }
  }
}